Theory And Experimental Investigation Of Two-dimensional Supersonic Air Ejector

The designing theory , numerical simulation and experimental investigation were performed to study the two-dimensional supersonic air ejector in this paper.Firstly, one-dimensional designing theory of supersonic air ejector was studied and the calculated flow process chart was established. The results proved that small ejected number and high Mach-number were the optimal choice for high compression ratio air ejector.Then, numerical simulation was applied to experimental models. The numerical simulation results demonstrated that ejecting total-pressure, ejecting Mach-number and entrance area ratio were key factors that influenced the pressure of blind cavity in starting status, minimizing contraction ratio and increasing the ratio of the shroud length/diameter were effective means to improve ejector performance, supersonic -supersonic ejector was superior to subsonic-supersonic ejector in mixing performance.Finally, schlieren technique and pressure measurement were combined to study the experimental investigation of one stage and two stage supersonic air ejectors. The following conclusions were based upon the results of experimental investigation:1. The criterion was proposed for the condition that the total pressure is too low to start.2. It was showed that the flow field of numerical simulation was correct proved by the schlieren photographs.3. Flow filelds of supersonic - supersonic ejecting style were found in the experiments by the schlieren photographs.4. Pressure matching conditions of attaining supersonic-supersonic ejecting method were analysed.These conclusions in this paper were meaningful and helpful to the applications and basic studies of supersonic air ejector.